1. Field of the Invention
The present invention relates to a connector for a shielded wire. More particularly, the present invention relates to a connector capable of facilitating processing of an end portion of a shielded wire.
The present application is based on Japanese Patent Application No. Hei. 11-120213, which is incorporated herein by reference.
2. Description of the Related Art
As shown in FIGS. 6 and 7, a shielded wire 60 comprises a conductor 61, an insulating layer 62 for coating the conductor 61, a braided conducting shield 63 for covering the insulating layer 62, and an insulating sheath 64 for covering the braided conducting shield 63.
A related connector 70, connected to an end portion of the shielded wire 60, comprises a cylindrical main body 71, a connection portion 72 formed at one end portion of the main body 71 (the left side of FIGS. 6 and 7), a clamp 73 to be inserted into the main body 71 from the other side thereof (i.e., the right side of the main body 71), a gasket 74, a washer 75, and a clamp 76.
The main body 71 is made of an appropriate metal capable of establishing conduction with the braided conducting shield 63, and a rib 77 is formed along the interior circumferential surface of the main body 71 so as to extend in the radial direction. Further, an insulating sleeve 78 is provided between the rib 77 and the connection portion 72.
The connection portion 72 is formed into a cylindrical shape, is concentrically rotatable relatively to the main body 71, and is to be connected to a connection portion of another connector or that of predetermined equipment, by way of a female thread 79 formed along the interior circumferential surface of the connection portion 72.
The clamp 73 is formed into a stepped cylindrical shape, and each of the gasket 74 and the washer 75 is essentially formed into a disk-like shape of predetermined thickness. The clamp 73, the gasket 74, and the washer 75 are retained within the main body 71 while being stacked, by screw-engaging the substantially-cylindrical outer peripheral surface of the clamp 76 with the interior surface of the main body 71.
In order to connect the end portion of the shielded wire 60 to the connector 70, the conductor 61 is exposed a predetermined length in advance from the shielded wire 60, and then a center contact 65 is soldered to the exposed end portion of the conductor 61. Further, the shielded wire 60 is axially passed through the clamp 73, the gasket 74, and the washer 75.
Next, the braided conducting shield 63 is folded back such that the insulating layer 62 is exposed a predetermined length, and the clamp 73 is interposed between the leading end portion of the braided conducting shield 63 and the insulating sheath 64 as shown in FIG. 6.
Finally, the center contact 65 is axially inserted into the insulating sleeve 78 from one end portion of the main body 71, to thereby protrude from the connection portion 72. Further, the clamp 76 is screw-engaged with the main body 71, wherewith the end portion of the shielded wire 60 is fixedly pressed into the main body 71 by way of the clamp 73, the gasket 74, and the washer 75 such that the end portion of the insulating layer 62 and a folded-back portion 66 of the braided conducting shield 63 abut against a rib 77 of the main body 71, thereby connecting the end portion of the shielded wire 60 with the connector 70 as shown in FIG. 7.
In the meantime, connecting the connector 70 with the shielded wire 60 may involve a troublesome operation, because it is necessary to complicatedly treat the end portion of the shielded wire 60 after axially inserting in advance the end portion of the shielded wire 60 into the clamp 73, the gasket 74, the washer 75, and the clamp 76, and further, it is necessary to fixedly press the end portion of the shielded wire 60 into the main body 71 by way of a plurality of components.
In particular, the connector 70 is usually shipped and transported after individual components of the connector 70 are assembled into a single assembly. However, when the connector 70 is connected to the end portion of the shielded wire 60, the connector 70 has to be re-assembled after having been disassembled into individual components. Accordingly, double assembling operations are needed.
Further, since the connector 70 requires many components of comparatively high precision, a high manufacturing cost may be required.
The present invention has been conceived in light of the foregoing drawbacks. An object of the present invention is to provide a connector simplifying treatment of the end portion of a shielded wire and reducing the number of components.
To achieve the above object, according to the first aspect of the present invention, there is provided a connector connectable to an end portion of a shielded wire which includes a conductor, an insulating layer coating the conductor, a braided conducting shield covering the insulating layer, and an insulating sheath covering the braided conducting shield, the connector allowing axial insertion of the conductor of the shielded wire while insulating the conductor, the connector comprising a cylindrical main body insertable between the braided conducting shield and the insulating sheath in a longitudinal direction of the shielded wire so as to electrically connect to the braided conducting shield, a connection portion provided at a base end portion of the main body in an inserting direction in which the main body is inserted between the braided conducting shield and the insulating sheath, and a main-body-diameter reducing mechanism for reducing a diameter of a leading end portion of the main body in the inserting direction thereof.
Herein, as the structure of the main body for ensuring conduction with the braided conducting shield and insulation of the conductor, there may be employed a structure for causing a conductor to axially pass through the main body without involving a contact with the main body by setting the minimum internal diameter of the main body to be greater than the external diameter of the conductor, or a structure for causing a conductor to axially pass through the main body by setting the internal diameter of the main body to be greater than the diameter of the insulating layer.
There may also be employed a structure for fitting the insulating sleeve along the interior circumferential surface of an insertion hole through which the conductor is axially passed.
In the connector having the foregoing structure, the diameter of the main body inserted between the braided conducting shield and the insulating sheath is reduced, and therefore, the main body holds the braided conducting shield. Accordingly the connector can be connected with the end portion of the shielded wire.
More specifically, the connector of the present invention eliminates the necessity of complicated preliminary operations, which would have been required by the related connector. In contrast with the related connector, the connector of the present invention can reduce the number of components, and does not require a high precision to the components.
Accordingly, in comparison with the related connector, the connector of the present invention can simplify the operations required for connecting the end portion of the shielded wire to the braided-shield connector, and therefore, the manufacturing costs are reduced.
Further, according to the second aspect of the present invention, it is preferable that the main-body-diameter reducing mechanism includes at least one main body slit formed in the main body so as to extend from the leading end portion of the main body to a predetermined position in a longitudinal direction of the main body, and a main body nut formed on an exterior surface of the main body, and wherein the main body and the main body nut are brought into contact with each other by way of either a truncated-cone surface or a tapered surface which is tapered in a vicinity of an end portion of the main body slit toward the leading end portion of the main body in the inserting direction thereof.
The main body slit may correspond to a slit which is formed into a linear, curved, or helical shape in the longitudinal direction of the main body. The number of main body slits is arbitrary.
In a case where a plurality of main body slits are formed in the main body, for example, the slits may be formed so as to originate from positions along the generating line of the main body, wherein the positions are centered on the axis of the main body and spaced uniform intervals apart from one another in a circumferential direction.
Further, the truncated-cone surface may be formed such that the end portion of the main body slit of the main body serves as a large-diameter portion.
On one hand, the tapered surface may be formed so as to be tapered from one end portion to the other end portion of the main body nut on the interior circumferential surface of the main body nut.
Either the truncated-cone surface or the tapered surface or both of them may be employed as the main-body-diameter reducing mechanism.
In a case where both the truncated-cone surface and the tapered surface are used in combination as the main-body-diameter reducing mechanism, there is no necessity of bringing the truncated-cone surface into surface contact with the tapered surface. The truncated-cone surface may be brought into contact with the main body independently of the tapered surface being brought into contact with the main body nut.
The connector having the foregoing structure employs the main-body-diameter reducing mechanism for bringing the main body into contact with the main body nut by way of the truncated-cone surface and the tapered surface. Therefore, the diameter of the leading end portion of the main body is reduced by screwing the main body nut relative to the main body while the width of the main body slit is reduced.
Namely, in the connector, the main body and the main body nut, the main body readily and firmly holds the braided conducting shield through extremely simple operations; that is, screw-engagement of the main body nut with the main body. Accordingly, the connector can be connected to the end portion of the shielded wire. In the connector, the diameter of the main body can be reduced in a stepless manner by screw-engagement of the main body with the main body nut, thereby offering versatility to braided conducting shields of different diameters.
Further, according to the third aspect of the present invention, it is preferable that an interior circumferential surface of the main body is formed into a stepped geometry including a large-diameter portion and a small-diameter portion, an end surface of the braided conducting shield can abut against a stepped surface between the large-diameter portion and the small-diameter portion, and an insulating sleeve is fitted around the small-diameter portion.
In the connector, the end surface of the braided conducting shield can abut against a stepped surface, thereby limiting the position of the main body relative to the shielded wire. Thus, there can be obviated the chance of the main body endlessly entering the space between the braided conducting shield and the insulating sheath.
In the connector, the insulating sleeve is fitted around the small-diameter portion, and therefore, the conductor can be unfailingly insulated from the main body.
Further, according to the fourth aspect of the present invention, it is preferable that the main body has a cross section longitudinally tapered toward the leading end portion of the main body in the inserting direction thereof.
Herein, the main body may be provided with both or either an interior tapered surface which originates from a predetermined position on the interior circumferential surface of the main body and spreads toward the leading end portion of the main body in the inserting direction thereof, or a cone-shaped exterior tapered surface which originates from a predetermined position on the exterior surface of the main body and is oriented toward the leading end portion of the main body in the inserting direction thereof.
In the connector, since the main body has a tapered cross section, the main body can be readily inserted into the space defined between the braided conducting shield and the insulating sheath, thereby facilitating an operation required for connecting the connector with the shielded wire. There can be reduced the chance of the end surface of the braided conducting shield and that of the insulating sheath being damaged.
Next, according to the fifth aspect of the present invention, the connector may further comprises an engagement mechanism for causing the main body to engage in an exterior circumferential surface of the insulating sheath, wherein the engagement mechanism includes a cylinder portion which is connected to the main body nut and extends along the exterior circumferential surface of the insulating sheath, a claw formed on an interior circumferential surface of the cylinder portion at an open end portion of the cylinder portion, and a cylinder-portion-diameter reducing mechanism which reduces a diameter of the open end portion of the cylinder portion.
Herein, the claw may be formed into a rib-like shape, a chevron-like cross sectional shape, a pyramid-like cross sectional shape, a cone-like cross sectional shape, a spherical cross sectional shape, or the like.
As in the case of the main-body-diameter reducing mechanism, there may be employed, as a cylinder-portion-diameter reducing mechanism, a structure embodied by forming slit in a cylinder portion in the longitudinal direction thereof, and causing an appropriate engagement member to screw-engage with the exterior surface of the base end portion of the cylinder portion in the inserting direction thereof, by way of the truncated-cone surface or tapered surface.
In the connector, when the diameter of the cylinder portion is reduced by the cylinder-portion-diameter reducing mechanism, the claw formed on the cylinder portion is brought into engagement in the exterior circumferential surface of the insulating sheath by way of the cylinder portion and the main body nut, thereby ensuring the relative position of the main body with respect to the insulating sheath.
Namely, in the connector, the position of the main body relative to the shielded wire can be maintained, thereby enabling unfailing connection of the main body with the end portion of the shielded wire.
Further, according to the sixth aspect of the present invention, the cylinder-portion-diameter reducing mechanism may include a cylinder slit formed in the cylinder portion so as to extend in a longitudinal direction thereof, and a cylinder nut to be screw-engaged with an outside of the main body nut, wherein the main body and the main body nut are brought into contact with each other by way of either a truncated-cone surface or a tapered surface, which is tapered in the vicinity of the end portion of the main body slit toward the leading end portion of the main body in the inserting direction thereof.
Herein, as in the case of the main body slit, the cylinder slit may correspond to a slit which is formed in a linear, curved, or helical shape in the longitudinal direction of the main body. The number of main body slits is arbitrary.
As in the case of the main-body-diameter reducing mechanism, the cylinder-portion-diameter reducing mechanism employs either a truncated-cone surface or a tapered surface or both.
Accordingly, in the connector, the main body can be readily, unfailingly engaged with the braided conducting shield through considerably simple operations; that is, screw-engagement of the nut of the cylinder portion with the main body nut. The diameter of the main body can be reduced in a stepless manner by screw-engagement of the cylinder portion nut with the main body nut, thus offering versatility to braided conducting shields having insulating sheathes of different diameters.